Static stirrer apparatus and process

ABSTRACT

A static stirrer apparatus and process for use in agitating a fluid while elevating the temperature of the same fluid uniformly wherein a heating means for transferring heat to said fluid and elevating the temperature thereof is surrounded by a sleeve means providing a passageway for movement of fluid along the heating means, the sleeve means having an intake opening at its lower end, the fluid surrounding the sleeve means being transferred through the intake opening into the passageway and moved along the heating means through an outlet opening disposed in the upper portion of the sleeve means by convection. A static stirrer apparatus and process wherein the movement of fluid along the heating means within the sleeve means is effective to agitate the fluid surrounding and being heated by the heating means.

United States Patent 1191 Bhasin I et.2,11973 l l STATIC STIRRERAPPARATUS AND PROCESS [75] Inventor: Harish P. Blltasin, Chicago, Ill.

[73] Assignee: Ceneo Incorporated, Chicago, 111.

[22] Filed: June 24, 19711 [21] Appl. No.: 156,302

[52] US. Cl 165/108, 219/316, 219/523 [51] lnt. C1. 111051) 3/40 158]Field 01' Search 165/108, 128, 132; 219/319, 314, 322, 323, 523

[56] References Cited UNITED STATES PATENTS 3,614.386 10/1971Hepplewhite 219/316 1379671 5/1921 Abtmeyer .7 219/523 PrimaryExaminerWilliam F. O'Dea Assistant ExaminerWilliam C. AndersonAttorney-Robert E. Wagner [57] ABSTRACT A static stirrer apparatus andprocess for use in agitating a fluid while elevating the temperature ofthe same fluid uniformly wherein a heating means for transferring heatto said fluid and elevating the temperature thereof is surrounded by asleeve means providing a passageway for movement of fluid along theheating means, the sleeve means having an intake opening at its lowerend, the fluid surrounding the sleeve means being transferred throughthe intake opening into the passageway and moved along the heating meansthrough an outlet opening disposed in the upper portion of the sleevemeans by convection. A static stirrer apparatus and process wherein themovement of fluid along the heating means within the sleeve means iseffective to agitate the fluid surrounding and being heated by theheating means.

2 Claims, 3 Drawing Figures STATIC STllRlREiR APPARATUS AND PROCESSBACKGROUND OF THE INVENTION This invention relates to a process andapparatus for thermodynamically agitating a fluid while elevating thetemperature of said same fluid uniformly.

One of the most common methods of heating various types of fluids inboth laboratory and industrial applications today is by placing aheating element within the receptacle or body containing such fluids andpermitting this element to transfer heat to the fluid by conductionthereby eventually elevating the temperature of any given molecule offluid by a certain minimum degree.

This method of conductive heating has the advantage of being both simpleand inexpensive. There are major disadvantages to this method, however,and among these are the fact that heating elements used in this mannerare subject to having certain minerals contained in the fluids in whichthey are immersed deposited on them in the course of heating suchfluids. Such mineral deposition substantially decreases the useful lifeof these heating elements and necessitates continual replacement orcleaning of the elements in order to keep them in working order. Thecrust formed on the heating elements also reduces the efficient heatingability of such elements.

In addition, because of the fact that the heating element raises thetemperature of the fluid in close proximity to it much faster and to agreater degree than fluid located at some distance from the elementitself, heating of the fluid within the receptacle or body in which itis contained is accomplished in a non-uniform manner. This isundesirable because it sets up distinct thermal gradients throughout thefluid in the container, particularly between the fluid at the surfaceand the fluid in the bottom portion of the vessel. In this layering ofthermal gradients, the temperature differential between the surfacefluid and the bottom fluid is such that the surface fluid is at a highlyelevated temperature in comparison with the bottom fluid. Likewise, thedifferential between the fluid surface temperature and the temperatureof the surrounding atmosphere is also greater than it would be withuniform heating of the fluid and thus a greater heat loss is sufferedthan would be suffered if heating were uniformly accomplished.

- DESCRIPTION OF THE INVENTION The static stirrer apparatus and processof this invention involves the placing of a protective sleeve of novelconfiguration around a conventional heating element, this sleeve beingeffective to prevent the deposition of minerals on the heating elementwhile at the same time providing for a uniform elevation of temperaturethroughout the fluid within which the heating element is placed, thuseliminating drastic temperature gradients within the fluid.

The apparatus and process of this invention causes this thermodynamicstatic stirring and uniform heating by drawing fluid having the lowestrelative temperature of that contained in the receptacle or body into apassageway formed by the sleeve around the heating element, transferringthis fluid along the operating heating element which raises thetemperature of this fluid causing it to be convected out throughopenings in the top portion of the sleeve into the remainder of thefluid to be heated. This movement by the thermodynamic phenomenon ofconvection accomplishes static stirring of the fluid surrounding theheating element, also agitating or mixing the fluid in the receptaclewithout foaming. By acting on the lowest temperature fluid first, italso accomplishes a much more uniform elevation of temperaturethroughout the body of the fluid.

To effectively provide for the intake of low temperature fluid first,the present invention has at the lower end of the sleeve means anannular flange held in spaced relation above a plate by a plurality ofsupport means. The flange and plate are of much greater diameter thanthe sleeve means so that fluid located at a distance from the heatingelement is drawn into contact with the heating element first.

The present invention is adaptable for use in either scientific orindustrial heating procedures and may be used by simply changing itsconfiguration to conform to the configuration of any type of heatingelement. In principle, this static stirrer is also adaptable for use inany size receptacle or body containing fluid, such as a beaker, flask,drum, tub, etc., where uniform heat distribution and elimination ofthermal gradients are desirable.

This invention is also adaptable for use with a cooling element whereuniform lowering of a temperature of a fluid is desired by merelyinverting the sleeve means so that the intake flange is located near thetop portion of the sleeve means.

Accordingly, it is an object of this invention to provide a process andapparatus for the elimination of min eral deposition on heating elementsimmersed in and operating in fluids.

It is a further object of this invention to provide a process andapparatus of the character described and having intake means of suchdimension and located in such a manner that uniform heating of a body offluid is accomplished and severe thermal gradients are eliminated.

It is a still further object of this invention to provide an apparatusand process combining thermodynamic static stirring designed toeliminate mineral deposition on a heating element while agitating ormixing fluid without foaming with uniform elevation of the temperatureof the fluid being heated by such heating element.

It is also an object of this invention to provide an apparatus acting incombination with a conventional heating element to prevent deposition ofminerals on such element and to produce uniform heating of the fluidsurrounding such element.

These and other important objects of the present invention will becomeapparent from the following description taken in conjunction with thedrawings illustrating a preferred embodiment wherein:

FIG. 11 is a perspective view of the static stirrer apparatus;

FIG. 2 is a vertical cross-sectional view of the static stirrerapparatus immersed in a receptacle containing a volume of fluid; and

FIG. 3 is an enlarged vertical cross-sectional view of the top portionof the static stirrer apparatus.

Referring now to the drawings and more particularly to FIG. l, thestatic stirrer apparatus lltl has a heater assembly Ill including aheating means or element 12 connected by plug 13 or other suitable meansof connection to a source of electricity (not shown) or other suitableheat source.

The heating means 12 is surrounded by a sleeve means or tube 14 alongthe portion of its length which is to be immersed into the fluid to beheated. The sleeve means 14 is of hollow cylindrical configuration andopens at the lower end 15 of the sleeve means 14 to an intake opening 16formed by an annular flange 18, which is connected to the lower end 15of the sleeve means 14, and which extends outwardly beyond thecircumference of the sleeve means 14. Below the annular flange 18 is abase plate 20 which is held in spaced relation from the annular flange18 by support means or spacers 22 disposed between the base plate 20 andthe annular flange 18.

The sleeve means 14 has disposed in its upper portion outlet openings orports 24 through which the fluid within the sleeve means 14 istransferred out of the sleeve means 14 into the surrounding volume offluid.

The top end 25 of the sleeve means 14 may be sealed to the atmosphere asshown in FIG. 3 by a sleeve cap seal 26 which is attached to the sleevemeans 14 about the circumference of the sleeve means 14 and through thecenter of which is disposed the heating means 12. The sleeve cap seal 26is then attached to the heating means 12 about the periphery of saidheating means 12. The sleeve cap seal 26 thereby serves to not onlysupport heating assembly 11 within the fluid to be heated but also toprevent excessive surface heat loss across the fluid-atmosphereinterface in the sleeve means 14. Although use of the sleeve cap seal 26is therefore preferred, such use is not necessary to the efficientoperation of the static stirrer apparatus unless it is submerged.

In the operation of the static stirrer apparatus and process, theheating means 12 surrounded by sleeve means 14 is immersed in a fluid tobe heated contained in a receptacle or container 28 as shown in FIG. 2.The lower end 15 of the sleeve means 14 is positioned near the bottom ofthe receptacle 28. The intake opening 16 formed by virtue of the largediameter annular flange l8 spaced above base plate 20 by support means22 is effectively located near the corners of receptacle 28 which wouldordinarily contain the volume of fluid last to be heated and, therefore,having the lowest relative temperature within receptacle 28 if heatingwere attempted to be accomplished by theremal conduction as it normallyis accomplished. By use of the sleeve means 14 and the novel enlargedintake opening 16, however, the portion of fluid nearest the intakeopening 16, that is, that in corners of receptacle 28, is drawn intoopening 16 first when the heating means 12 begins to operate by thephenomenon of convection. In convection, the fluid contained initiallyin the passageway 30 formed along heating means 12 by the sleeve means14 surrounding it is heated, thereby decreasing its density so that suchless dense heated fluid moves upward along passageway 30, through thesleeve means 14 and a volume of fluid to be heated is drawn in throughthe intake opening 16 to take its place. As the volume of fluid to beheated is transferred from the intake opening 16 toward the passageway30 and the heating element 12, its temperature is raised by operation ofthe heating means 12 which radiates heat throughout the area of thepassageway along which the unheated volume of fluid travels. As itstemperature is raised, the density of the fluid volume is similarlyreduced and such volume of fluid thereby continues to move upward alongthe passageway 30. By the time a particular volume of fluid reaches theupper portion of the sleeve means 14, it has attained its maximumtemperature and minimum density. This volume of fluid is thentransferred into the portion of fluid surrounding the sleeve means 14through outlet ports or openings 24 disposed in the upper portion of thesleeve means 14.

This upward movement of fluid along the passageway 30 by convectioncauses a stirring effect which prevents the deposition of minerals onthe heating element 12.

While some heating of the body of the fluid contained in receptacle 28takes place by convection, the primary method of heating remains that ofconduction. However, the use of the intake opening 16 having a dimensiongreater than that of the sleeve means 14, so that the coldest, mostdense portion of fluid in the receptacle 28 is drawn into the passageway30 first, serves to substantially eliminate the drastic thermalgradients which result from heating a body of fluid by conduction alone,since the static stirrer apparatus and process acting on the principlesof convection forces the coldest, densest fluid, located in the areas ofthe receptacle 28 ordinarily heated last under the conduction method, tobe heated first.

The static stirrer apparatus may be constructed of any suitable materialhaving a high thermal conductivity, subject to being easily shaped orformed, and resistant to corrosion by the fluids in which it isimmersed, such as stainless steel, stainless steel alloys, aluminum, andother suitable metal alloys.

While the invention has been described in relation to a preferredembodiment thereof, it will be apparent to those skilled in the art thatthe structural details are capable of wide variation without departingfrom the principles of the invention.

I claim:

1. A static stirrer apparatus for use in agitating a fluid contained ina receptacle thermodynamically while elevating the temperature of saidfluid uniformly, comprising heating means for transferring heat to saidfluid and elevating the temperature thereof, sleeve means surroundingsaid heating means and providing a passageway for the movement of saidfluid therealong, said sleeve means confining said fluid to saidpassageway to facilitate heat transfer between said heating means andsaid fluid, said sleeve means having a fluid inlet opening at its lowerend and a plurality of fluid outlet openings disposed along an upperportion thereof, said fluid inlet opening including an annular flangeformed at the lower end of said sleeve means and a base plate means heldin spaced relation beneath said flange by support means, said flange andsaid base plate extending outwardly beyond the edge of said sleeve meansa radial distance substantially greater than the diameter of said sleevemeans and slightly less than the corresponding dimension of saidreceptacle to provide for movement of that portion of said fluidcontained in said receptacle and disposed at a substantial distance fromsaid heating means and having the relative coldest temperature in saidreceptacle into said passageway formed by said sleeve means first toassure uniform heating of all fluid contained in said receptacle, saidplurality of fluid outlet openings providing a number of outlet meansfor movement of fluid out of the passageway formed by said sleeve meansin response to the temperature gradient established in said fluid byheat transfer, the numing element and said sleeve means to therebyprevent excessive upward surface heat loss across the interface betweenthe fluid confined in said passageway and the atmosphere.

1. A static stirrer apparatus for use in agitating a fluid contained ina receptacle thermodynamically while elevating the temperature of saidfluid uniformly, comprising heating means for transferring heat to saidfluid and elevating the temperature thereof, sleeve means surroundingsaid heating means and providing a passageway for the movement of saidfluid therealong, said sleeve means confining said fluid to saidpassageway to facilitate heat transfer between said heating means andsaid fluid, said sleeve means having a fluid inlet opening at its lowerend and a plurality of fluid outlet openings disposed along an upperportion thereof, said fluid inlet opening including an annular flangeformed at the lower end of said sleeve means and a base plate means heldin spaced relation beneath said flange by support means, said flange andsaid base plate extending outwardly beyond the edge of said sleeve meansa radial distance substantially greater than the diameter of said sleevemeans and slightly less than the corresponding dimension of saidreceptacle to provide for movement of that portion of said fluidcontained in said receptacle and disposed at a substantial distance fromsaid heating means and having the relative coldest temperature in saidreceptacle into said passageway formed by said sleeve means first toassure uniform heating of all fluid contained in said receptacle, saidplurality of fluid outlet openings providing a number of outlet meansfor movement of fluid out of the passageway formed by said sleeve meansin response to the temperature gradient established in said fluid byheat transfer, the number of openings being sufficient to agitate or mixthe fluid contained in the receptacle without foaming.
 2. The staticstirrer apparatus of claim 1 including cap means covering the top end ofsaid sleeve means, said cap means being hermetically sealed to saidheating element and said sleeve means to thereby prevent excessiveupward surface heat loss across the interface between the fluid confinedin said passageway and the atmosphere.